Field of the Invention
The present invention relates to door lock devices, and more particularly to an intelligent door lock system with an off center drive mechanism.
Description of the Related Art
Many house, locks and apartment locks and the like, include a lock cylinder and a lock bolt that can be brought to a locked or unlocked state with the aid of a key from inside and outside the door to which the lock is fitted. A thumb turn is mounted on the inside of the door and that has the same function as the key. The purpose of the thumb turn is to enable the lock to be brought to a locked and unlocked state without needing to use a key. One drawback with this solution is that a person who has unlawfully obtained access to the inside of the door, for instance through a window, can easily unlock the door by means of the thumb turn and then leave the room through the normal exit.
Locks that include a thumb turn latch are known. With these, a person in the possession of a valid key, for instance the owner of an apartment, is able to latch the thumb turn function and thereafter use the key to lock the door. Anyone located on the inside of the door is then unable to leave the room through the locked door, and must therefore find another exit.
In the case of some known locks of this nature, the thumb turn latch is activated by means of a switching element on the forend side of the lock, wherein the switching element is moved to a specific position in which said latch is activated, prior to locking the door with the key. One drawback with this known solution, however, is that a person who intends to enter locked premises unlawfully other than through the door, can determine whether or not the latch has been activated, by peering through the crack in the door and therewith determining the position of the switching element. A further drawback with known thumb turn latches is that their function contributes significantly to the number of lock components, resulting in higher costs both with respect to manufacture and with lock assembly/fitting.
However, on a mounting plate, it is difficult to mount the thumb door latch with it coinciding with a center of rotation for the mechanism.
Accordingly, there is a need for an improved door latch. There is a need to provide a deadbolt that can be retrofitted to an existing door. There is another need for an intelligent door lock system with an off center drive mechanism. There is a further need for an intelligent door lock system with an off center drive mechanism that utilizes a variety of position sensing devices including but not limited to, accelerometers, optical encoders, magnetic encoders, mechanical encoders, Hall Effect sensors, potentiometers, contacts with ticks and the like, that is positioned on a drive shaft, or on an element coupled to the drive shaft. There is a further need for an intelligent door lock system where a position of a drive shaft, coupled to a dead bold, is used to detect if the dead bold, lock, is locked, unlocked, a depth of the dead bold travel and the like, and an off center drive mechanism is provided that allows up to R displacements of the lock, where R is the radius of the lock.